This invention relates to a vacuum assisted toilet that uses less water than a conventional toilet. Specifically, the invention refers to a method and apparatus for creating a vacuum downstream of the toilet and upstream of a discharge pipe leading to a sewer pipe or a waste holding tank.
Reducing the amount of water used for each flush has long been a goal of designers of waste removal, or toilet systems. Pursuing this goal has been attempted predominantly in two ways. First, designers have implemented pressurized water holding tanks above the toilet so that water at elevated pressure levels enters the bowl during the flush cycle. Second, designers have applied a vacuum force downstream from the toilet. This second approach, in turn, can be divided generally into two categories. The first category is demonstrated by airplane toilet systems. In these devices a vacuum is applied downstream from a holding or receiving tank. Thus, the vacuum force is applied both to the receiving tank, the discharge trapway and the toilet. The second category of vacuum assisted toilets in the art is a vacuum situated along the discharge trapway that ramps up in intensity as the flushed water evacuates the bowl.
The shortcoming of each of these types of vacuum assisted toilets is that the evacuator force of the vacuum is used inefficiently. The less water used during a flush, the more efficient a toilet is. In the airplane toilet systems, the evacuator force is not applied in the discharge trapway alone. Rather, the vacuum is applied to a holding tank as well. It is in the discharge trapway where the vacuum is most needed. When the evacuator force has been applied along the discharge trapway, it has been inefficient in that the force increases in intensity only when the leading edge of the flushed water has passed. As a result, the highest levels of evacuator force produced by the prior known devices is directed to the flushed water in a direction away from the holding or receiving tank.
It would be desirable to provide a toilet system where vacuum is created between the toilet and the discharge piping or a receiving tank, such that the vacuum acts to draw the flushed water from the toilet, through the discharge piping, and to the receiving tank. Further it would be desirable to apply this evacuator force at a location along the discharge passage so that the maximum amount of force is applied to draw the contents of the toilet bowl out of the toilet bowl and into the discharge piping.